Bump rsession version

[yuvipanda]

We bumped rstudio in
#107,
I think we need to bump this too

[GeorgianaElena]

Unfortunately, this made RStudio disappear completely :(

I'm seeing this error in the logs:

[W 2021-09-23 12:35:23.018 SingleUserNotebookApp notebookapp:1995] Error loading server extension jupyter_server_proxy
    Traceback (most recent call last):
      File "/opt/conda/lib/python3.8/site-packages/notebook/notebookapp.py", line 1988, in init_server_extensions
        mod = importlib.import_module(modulename)
      File "/opt/conda/lib/python3.8/importlib/__init__.py", line 127, in import_module
        return _bootstrap._gcd_import(name[level:], package, level)
      File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
      File "<frozen importlib._bootstrap>", line 991, in _find_and_load
      File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
      File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
      File "<frozen importlib._bootstrap_external>", line 843, in exec_module
      File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
      File "/opt/conda/lib/python3.8/site-packages/jupyter_server_proxy/__init__.py", line 1, in <module>
        from .handlers import setup_handlers
      File "/opt/conda/lib/python3.8/site-packages/jupyter_server_proxy/handlers.py", line 16, in <module>
        from jupyter_server.utils import ensure_async, url_path_join
    ImportError: cannot import name 'ensure_async' from 'jupyter_server.utils' (/opt/conda/lib/python3.8/site-packages/jupyter_server/utils.py)

It looks like somehow an old version of jupyter-server gets installed instead of the minimum required one (>=1.0).